1. Field of the Invention
Aspects of the present invention relate to a disc, and more particularly, to an information recording medium, a recording/reproducing apparatus, and a recording/reproducing method with write-protection function.
2. Description of Related Art
In line with the developments of optical disc technologies and semiconductor technologies, new functions are frequently added to optical systems using drive systems for operating optical discs, after the specifications of the optical systems have been initially established. In such cases, the initially established specifications must be updated.
If a previous specification is called an “old specification” and an updated specification obtained by adding a new function is called a “new specification”, a disc according to the old specification is manufactured to be operable in a drive system according to the old specification. In contrast, a disc according to the new specification is manufactured to be operable in a drive system according to the new specification.
The old specification and the new specification may or may not be recording/reproducing compatible due to the newly added function. The fact that the two specifications are recording/reproducing compatible means that the disc according to the old specification can be used in the drive systems according to both the old specification as well as the new specification. Additionally, the disc according to the new specification can be used in the drive system according to both the new specification and the old specification. In this way, in order to ensure the recording/reproducing compatibility between the two specifications when a new function is added to the old specification to create the new specification, when a disc according to the new specification is loaded into a drive system according to the old specification, the drive system according to the old specification should be able to operate according to the new function. Allowance for such future new functions and new specifications should be accounted for at the time of establishing the old specification.
More specifically, in order to ensure the recording/reproducing compatibility among a series of specifications, such possibility should be accounted for at the time of establishing each of the specifications. When a new specification is established by adding a new function to an old specification and information regarding operations corresponding to the new function that a drive system according to the old specification should perform are stored in a disc, the operations for the new function should be performed even when a new disc having the newly added function is loaded onto the drive system according to the old specification. In this regard, it is possible to develop a write-protection function for data ensuring the recording/reproducing compatibility between different specifications.
When a write-protection function is embedded in a disc A which is loaded onto a drive system A by the use of the data for recording and reproducing compatibility, as shown in FIG. 1, control information for accessing the data for recording and reproducing compatibility in which the write-protection function is set must be recorded in a prescribed area of the disc A. However, since the write-protection function is already set, it is impossible to write data to the information recording medium any more. Accordingly, when the disc A is ejected from the drive system A and is reloaded onto the drive system A or is loaded onto another drive system, the drive system obtains only the previous control information from the information recording medium since recently updated control information is not recorded in the information recording medium. As a result, there is no way to recognize that the write-protection function is set to the medium. Therefore, there is a problem that the disc A is modified or changed contrary to the user's intention.